page_title: Dehalogenation
section_title: Dehalogenation using 1st row transition metal complexes
hierarchical_section_title: Dehalogenation / Dehalogenation using 1st row transition metal complexes
caption_attribution_description: English: Dehalogenation using Lithium chromium(I) dihydride
context_page_description: Dehalogenation is a chemical reaction that involves the cleavage of C-Halogen bond to form product. Dehalogenation can be divided into two subclasses: reductive dehalogenation and hydro dehalogenation.
context_section_description: Many groups have reported dehalogenation processes using different forms of homogeneous and heterogeneous transition metal complexes such as 0M, metal-ligand complexes, metal salts, and metal supported on different supports. 
  Vanadium compounds in its low oxidation state tends to perform dehalogenation reaction via one electron reduction. The efficiency of the one-electron transfer system depends on the redox potential of both the vanadium complexes and the radicophiles. Lithium chromium(I) dihydride has also been used as a versatile reducing agent to dehalogenate various alkyl or aryl halides as shown in scheme 3:
  Other than these metals, iron is the most studied metal for the dehalogenation reaction. Cahiez and his co-workers reported reduction of bromo-alkenes using manganese(II) halide in presence of Fe(acac)3. Inspired by this work, Mohammed and coworkers also performed hydrobromination of 1,1,-dibromo-1-alkenes in presence of Grignard agents and transition metals such as Fe and Cobalt. Macromolecules such as Hematin, cobalamin, vitamin B12, and coenzyme F430  are also used for dichlorination of polychlorinated ethylenes and benzenes. Charles and his co-workers reported that Vitamin B12 and coenzyme F430 were capable of sequentially dechlorinating tetrachloroethylene to ethylene, while hematin was demonstrated to dechlorinate tetrachloroethylene to vinyl chloride.
  
   
  Javier and his-coworkers reported the synthesis of Iron (II) fluoride complexes. The complexes were then used as precursor and precatalysts for hydrodefluorination of fluorocarbons. They reported the first synthesis of a three-coordinate iron-fluoride complex.
  
    
  Jayant and his coworkers developed two phase systems for dehalogenation of trichloroethylenes. The kinetic model provides reaction process to take place in one phase while mass transfer between two phases. 
  There have been several reports on dehalogenation process performed using various other metals such as cobalt, nickel, palladium, silicon, and germanium.
caption: Dehalogenation using Lithium chromium(I) dihydride
exif: {}